Arc Flash At Brookhaven National Laboratory April 14, 2006 - Energy
Type B Accident Investigation Board Report Arc Flash at Brookhaven National Laboratory April 14, 2006 August 2006 Brookhaven Site Office U.S. Department of Energy Upton, New York
Type B Accident Investigation of the Arc Flash at Brookhaven National Laboratory, April 14, 2006 Acronyms and Abbreviations AC Alternating Current AGS Alternating Gradient Synchrotron AHJ Authority Having Jurisdiction ASE Accelerator Safety Envelope ASSRC Accelerator System Safety Review Committee ATS Action Tracking System BNL Brookhaven National Laboratory BNL PE BNL Plant Engineering BHSO Brookhaven Site Office C-AD Collider-Accelerator Department CAS Collider Accelerator Support CRD Contractor Requirements Document DC Direct Current DOE Department of Energy EMT Emergency Medical Technician ESFD Experimental Support and Facilities Division ESH&Q Environment, Safety, Health, and Quality ES&H Environment, Safety, and Health ESRC Experimental Safety Review Committee FR Flame-Resistant FRA Facility Risk Assessment GE General Electric GFCI Ground Fault Circuit Interrupter ISM Integrated Safety Management ISMSD Integrated Safety Management System Description JON Judgment of Need JRA Job Risk Assessment JTA Job Training Assessment ii
Type B Accident Investigation of the Arc Flash at Brookhaven National Laboratory, April 14, 2006 LIPA Long Island Power Authority LOTO Lockout/Tagout NASA National Aeronautics and Space Administration NEC National Electrical Code NFPA National Fire Protection Association OMC Occupational Medical Clinic OPM Operating Procedure Manual ORR Operational Readiness Review OSHA Occupational Safety and Health Administration PPE Personal Protective Equipment PT Potential Transformer QAM Quality Assurance Manual QAP Quality Assurance Program RHIC Relativistic Heavy Ion Collider SAD Safety Assessment Document SBMS Standards-Based Management System SC Office of Science SEAPPM Safety and Environmental Administrative Policy and Procedures Manual S&EP Safety and Environmental Protection SLAC Stanford Linear Accelerator Center SME Subject Matter Expert STAR Solenoidal Tracker at RHIC UL Underwriters Laboratories iii
Type B Accident Investigation of the Arc Flash at Brookhaven National Laboratory, April 14, 2006 Disclaimer This report is an independent product of the Type B Accident Investigation Board appointed by Michael Holland, Manager, Brookhaven Site Office, U.S. Department of Energy. The Board was appointed to perform a Type B investigation of this accident and to prepare an investigation report in accordance with DOE O 225.1A, Accident Investigations, and DOE G 225.1-A, Implementation Guide for Use with DOE 225.1A, Accident Investigations. The discussion of facts, as determined by the Board, and the views expressed in the report do not assume, and are not intended to establish, the existence of any duty at law on the part of the U.S. Government, its employees or agents, contractors, their employees or agents, or subcontractors at any tier, or any other party. This report neither determines nor implies liability. iv
Type B Accident Investigation of the Arc Flash at Brookhaven National Laboratory, April 14, 2006 Release Authorization On April 17, 2006, I established a Type B Accident Investigation Board to investigate the April 14, 2006, arc flash incident at the Brookhaven National Laboratory (BNL) that resulted in first- and second-degree burns to a BNL electrical engineer. The Board’s responsibilities have been completed with respect to this investigation. The analysis process, identification of causal factors, and development of judgments of need were performed during the investigation in accordance with DOE O 225.1A, Accident Investigations. I accept the findings of the Board and authorize the release of this report for general distribution. Michael D. Holland Manager, Brookhaven Site Office v
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Type B Accident Investigation of the Arc Flash at Brookhaven National Laboratory, April 14, 2006 Table of Contents Acronyms and Abbreviations. ii Disclaimer. iv Release Authorization. v Executive Summary. xi The Accident. xi Background. xi Results and Analysis . xii Conclusions . xiii 1.0 Introduction . 17 1.1 Background . 17 1.2 Facility Description . 17 1.3 BNL Organizational History . 20 1.3.1 BNL Organization and the RHIC Project . 20 1.3.2 BNL Organization and the Collider-Accelerator Department. 23 1.3.3 DOE Organization and the RHIC Project . 24 1.4 2.0 Scope, Conduct, and Methodology . 24 The Accident . 25 2.1 Accident Overview . 25 2.1.1 2.1.1.1 Background. 26 2.1.1.2 Environmental Conditions. 32 2.1.1.3 Personal Protective Equipment and Clothing Requirements . 32 2.1.1.4 Description of Events Preceding Accident. 33 2.1.1.5 Emergency Response. 36 Evaluation of the Arc Flash. 38 2.2 2.2.1 2.3 Accident Description. 25 Electrical System Description and Damage Analysis . 38 2.2.1.1 Electrical System Description. 38 2.2.1.2 Description of Damage . 41 2.2.1.3 Possible Arc Flash Causes . 46 Training and Qualification . 50 vii
Type B Accident Investigation of the Arc Flash at Brookhaven National Laboratory, April 14, 2006 2.4 DOE Oversight . 52 2.5 BNL Oversight. 53 2.6 Investigative Readiness. 54 3.0 Analysis . 54 3.1 Barrier Analysis. 54 3.2 Change Analysis . 54 3.3 Events and Causal Factors Analysis. 54 3.3.1 Direct Cause. 55 3.3.2 Contributing Causes. 57 3.3.3 Root Cause. 57 3.4 Integrated Safety Management System Analysis. 58 3.4.1 Define the Scope of Work . 58 3.4.2 Analyze the Hazards . 60 3.4.3 Develop and Implement Hazard Controls . 61 3.4.4 Perform Work within Controls . 62 3.4.5 Provide Feedback and Improvement. 63 4.0 Judgments of Need. 65 5.0 Board Signatures . 69 6.0 Board Members and Advisors. 70 Appendix A: Board Appointment Memorandum . A-1 Appendix B: Arc Flash Accident Event Chronology . B-1 Appendix C: Barrier Analysis.C-1 Appendix D. Change Analysis .D-1 Appendix E: Events and Causal Factors Chart. E-1 List of Figures Figure 1-1. Brookhaven National Laboratory . 17 Figure 1-2. Building 1006A . 18 Figure 1-3. Electrical panel PB-1. 19 Figure 1-4. Kirk Key interlocks on switches 2A, 3A, 4A, and 5A . 19 Figure 1-5. Interim Organization Chart (1997). 21 viii
Type B Accident Investigation of the Arc Flash at Brookhaven National Laboratory, April 14, 2006 Figure 1-6. RHIC Organization Chart (1997) . 22 Figure 1-7. BNL Organization Chart (2006). 23 Figure 2-1. Circuit 64 designs for the 6A transformer (with alarm to control console) and 6C (without alarm to control console). 29 Figure 2-2. Location of BNL personnel when the arc flash occurred. 36 Figure 2-3. Substation 6C outside Building 1006A . 38 Figure 2-4. Partial one-line diagram substation 6C. 40 Figure 2-5. Bowed cover of Switch 3A. 41 Figure 2-6. Back of switch 3A bus cover plate . 42 Figure 2-7. Undamaged bus on undamaged switch . 42 Figure 2-8. Damaged Switch 3A . 43 Figure 2-9. Evidence of arcing between base and Phase B Switch 3A. 43 Figure 2-10. Space between screw ends on undamaged switch. 44 Figure 2-11. Switch 3A ABS base Phase B displaced piece. 44 Figure 2-12. Switch 2A ABS base Phase A and C displaced pieces . 45 Figure 2-13. Crack developing in ABS base of switch not involved in the accident. 45 Figure 2-14. Damaged cable which was underwater in manhole from substation 6C to panel PB-1 . 46 Figure 2-15. Damaged cable with oxidized copper . 46 Figure 2-16. Loose arc chute from 600-amp Spectra-fused disconnect switch. 48 Figure 2-17. Switch 3A (note location of contact clip). 49 Figure 2-18. Location of contact clip on Switch 3A after backing plate removed . 49 Figure 2-19. Contact clip from Switch 3A. 49 Figure 2-20. Switch 2A (note the ABS base pieces). 50 List of Tables Table ES-1. Judgments of Need and Causal Factors . xiv Table 1-1. Accident Investigation Terminology. 25 Table 2-1. Status of Ground-Fault Detection Alarms for C-AD Substations . 28 Table 2-2. Electrical Safety Training . 52 Table 3-1. Summary of Causal Factor Analysis. 55 Table 4-1. Judgments of Need and Causal Factors . 66 ix
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Type B Accident Investigation of the Arc Flash at Brookhaven National Laboratory, April 14, 2006 Executive Summary The Accident At 10:20 a.m., on April 14, 2006, a BNL Collider-Accelerator Department (C-AD) electrical engineer was injured by an arc flash at the Brookhaven National Laboratory (BNL) Relativistic Heavy Ion Collider (RHIC) when an arcing ground fault occurred across all three phases of a 480-volt, fuseddisconnect switch. The C-AD electrical engineer was in the process of restoring electrical power to the magnet power supplies for the Solenoidal Tracker at RHIC (STAR) detector and had just closed a switch in Building 1006A. The C-AD electrical engineer was not wearing the appropriate clothing and personal protective equipment (safety glasses) required for this work activity, and he received first- and seconddegree burns to his face and body. The extent of burns included first-degree burns on his face, scalp, and chest and first- and second-degree burns on his hands and forearms. Additionally, he received a corneal abrasion on his left eye and his hair was set on fire. After receiving medical treatment at a local hospital, the C-AD electrical engineer was released the same day. The Board concluded that the three-phase arcing ground fault was produced by an overvoltage condition resulting from a ground fault in a cable at the resonant frequency of the system. The Board could not rule out the possibility that a failure of the switch’s internal structure may have been a contributing cause to the arc flash. The existence of a ground fault was discovered 3 days before the accident, but this condition was not communicated to the RHIC Main Control Room, Chief Electrical Engineer, or Collider Accelerator Support (CAS) personnel. The overvoltage condition on the ungrounded delta power system was determined to be the direct cause of the accident. On April 17, 2006, the Site Office Manager for the U.S. Department of Energy (DOE) Office of Science (SC), Brookhaven Site Office (BHSO) appointed a Type B Accident Investigation Board to analyze the causal factors, identify the root causes, and determine judgments of need to preclude similar accidents in the future. The Board arrived onsite at BNL on April 17, 2006, and began the investigation. Background BNL is a multi-program national laboratory, established in 1947 on Long Island, Upton, New York. BNL operates under the programmatic direction of SC at DOE Headquarters, and is operated by Brookhaven Science Associates, LLC. The injured employee was a systems engineer for the STAR detector magnet power supplies. On the day of the accident, a power dip on the incoming power from the local utility caused fuses to blow in the magnet power supplies for the STAR detector. The RHIC Main Control Room received alarms from the STAR facility and requested support from CAS. The work activity to be conducted was to troubleshoot the magnet power supplies to determine what had caused the outage. The STAR Magnet power supplies were susceptible to blown fuses caused by power dips, which were a common occurrence. The power distribution system for RHIC and STAR is a three-phase, ungrounded delta system. The advantage to using an ungrounded delta electrical distribution system is that a line-to-ground fault does xi
Type B Accident Investigation of the Arc Flash at Brookhaven National Laboratory, April 14, 2006 not result in the operation of the overcurrent device, and the system continues to operate (as opposed to a solidly grounded system in which a ground fault would result in the operation of the overcurrent protection device). If a ground fault is not detected, the system continues to operate; but, if another fault occurs, it results in a line-to-line-to-ground fault, which has the potential for more severe damage to the electrical equipment and personnel exposure to electrical hazards. When ground-fault detection is installed and monitored, it allows steps to be taken to isolate the ground fault and make repairs in a safe and timely manner. BNL has had approximately 50 years of operating experience with ungrounded delta power systems. Disadvantages of ungrounded delta power supply systems include their vulnerability to switching surges and transient and resonant overvoltages. The power distribution system for the STAR Magnets was installed in 1997. RHIC requirements at the time of the STAR design, as well as current C-AD operating requirements, require remote monitoring of ground-fault conditions. Alarm response procedures for the RHIC Main Control Room specified prompt determination of the source of the ground fault (within 8 hours) and notification to the Chief Electrical Engineer if the source was not found. The National Electrical Code (NEC) at the time of the design recommended the use of monitoring equipment; the August 2004, NEC required that ungrounded electrical systems be provided with ground-fault monitoring. Substation 6C provides power to the electrical panel involved in the arc flash. This substation had a ground-fault detection relay installed, but it was inoperable because it did not have the required power source. The STAR control room and RHIC Main Control Room staff and the Chief Electrical Engineer were unaware that substation 6C did not have the capability to monitor ground-fault conditions. A surveillance of the voltages of substation 6C was performed 3 days before the accident; and, although a slight ground fault was recorded on the inspection form, no corrective action was taken. A ground fault on one of these cables resulted from a cut in the insulation and from the cable being submerged in a flooded manhole. Results and Analysis The accident resulted from a number of deficiencies in the implementation of a series of management systems and related processes. These weaknesses involved elements of the line organization, including the RHIC Project, C-AD, and Plant Engineering; the Environment, Safety, and Health Division; and BHSO. BNL had established design and operability requirements for the monitoring of ground-fault conditions on ungrounded power systems. However, BNL failed to ensure that these requirements were implemented in the design; verified in the engineering and environment, safety, and health design review and approval processes; tested following installation; confirmed in the Operational Readiness Reviews; and validated in commissioning activities. Although the ground-fault monitoring detection was a stated requirement in the RHIC Safety Assessment Document, this function was not verified to be operable. Ground-fault relays are important to the proper functioning of a safety feature; however, they were not included in a preventive maintenance program. The safe operation of ungrounded delta systems requires facility operators to take prompt action to determine the source of a ground fault and to take appropriate corrective actions. BNL failed to xii
Type B Accident Investigation of the Arc Flash at Brookhaven National Laboratory, April 14, 2006 implement formal work controls for working on ungrounded delta systems that could have a groundfault condition. BNL failed to implement National Fire Protection Association (NFPA) 70E, Standard for Electrical Safety in the Workplace. Arc flash calculations for Building 1006A were not completed. Upon completion of the arc flash calculations, BNL would have posted the appropriate personal protective equipment (PPE) on the electrical panel. The injured worker was not wearing the prescribed clothing and safety glasses while performing the work task. BNL failed to adequately monitor the implementation of NFPA 70E. BNL failed to implement NFPA 70, National Electrical Code (NEC) 2005 for ground-fault detection. The versions of the NEC prior to 2005 only recommended that ground-fault detection be provided for some specific applications of ungrounded electrical systems. NEC 2005 requires ground-fault detectors to be provided for ungrounded electrical systems. This code became effective in August 2004. BNL failed to ensure adequate implementation of the C-AD Conduct of Operations Program. Pre-job briefs were not held; personnel did not enforce stop work when a worker was not wearing proper protective equipment; surveillances of ground-fault conditions were not formalized through an approved procedure; and results were not communicated to operations and engineering management. BHSO failed to adequately validate BNL’s implementation of corrective actions from the Laboratory’s self-assessment and the Office of Science Energized Electrical Work. The Board could not rule out the possibility that the arc flash might have been caused by a switch failure; however, there was insufficient evidence to conclude that this was a likely failure mode. Conclusions The Board concluded that the accident was preventable. The overvoltage condition was the result of an undetected ground fault on an ungrounded system. The C-AD electrical engineer and the CAS electronic technicians were assigned to perform troubleshooting and fuse replacement tasks on a power system while it was in a ground-fault condition. The Board identified the root cause as BNL’s failure to ensure that good industrial practices, as well as Laboratory and applicable NFPA 70, National Electrical Code, requirements for the design, test, operation and maintenance of ungrounded delta electrical power distribution systems, were used at RHIC. The Board concluded that if these management processes and quality assurance requirements had been implemented, and if BNL had ensured that NFPA 70 E was effectively implemented, BNL workers would have been better protected in the event of an arc flash. The Laboratory and BHSO need to increase their emphasis on reducing worker exposure to electrical hazards. xiii
Type B Accident Investigation of the Arc Flash at Brookhaven National Laboratory, April 14, 2006 Table ES-1. Judgments of Need and Causal Factors No. Judgment of Need Causal Factor JON 1 BNL needs to conduct the following engineering evaluations of ungrounded delta electrical systems throughout the site: Ensure that instantaneous trip settings for power circuit breakers are reduced to the lowest value possible consistent with in-rush and load considerations and coordination with other overcurrent devices. Evaluate the installation of a dampening resistor across the broken delta points of all three-phase wye broken delta connected potential transformers that are connected to ungrounded 480-volt systems. Evaluate increasing the sensitivity of the groundfault detecting relays in all 480-volt ungrounded substations. Evaluate the installation of surge suppressors on all 480-volt ungrounded panel boards to suppress common-mode overvoltages and their related phase-to-ground flashovers. Perform an engineering evaluation on the continued use of ungrounded 480-volt power systems and consider conversion to highresistance ground systems. Verify that all potential transformers connected to ungrounded 480-volt systems are provided with ground-fault monitoring. BNL failed to ensure that good industrial practices, as well as Laboratory and applicable NFPA 70, National Electrical Code, requirements for the design, test, operation, and maintenance of ungrounded delta electrical power distribution systems, were used at RHIC. JON 2 BNL needs to immediately verify that all ground-fault BNL failed to ensure that ground-fault detector relays, monitoring devices are connected to remote alarms in as well as monitoring and alarm systems, were the RHIC Main Control Room. properly designed, installed, tested, and maintained. JON 3 BNL needs to determine and review the specific BNL failed to ensure that a ground-fault monitoring factors by which RHIC and Plant Engineering design system provided prompt notification to the Main reviews and approval processes failed to ensure Control Room for safe and reliable operation. installation of a functional ground-fault monitoring and alarm system as specified in BNL standards and DOE requirements. Additionally, BNL needs to implement the corrective actions identified by this review to prevent recurrence. JON 4 BNL needs to improve the rigor and formality of the engineering design and design review processes to ensure that the functional specifications identified in DOE Directives and BNL standards are addressed. xiv
Type B Accident Investigation of the Arc Flash at Brookhaven National Laboratory, April 14, 2006 No. Judgment of Need Causal Factor JON 5 BHSO needs to monitor BNL’s evaluation of the design review and approval processes. JON 6 BNL needs to improve the rigor and formality in acceptance testing, operational readiness review, and commissioning activities to ensure that the functional and performance specifications identified in DOE Directives and BNL Standards have been implemented. JON 7 BNL needs to ensure that all equipment necessary for safe and reliable operations of the RHIC (as described in the current Safety Assessment Document) has been verified to meet design specifications. JON 8 BNL needs to develop, train, and implement formal BNL failed to ensure that formal work controls were work controls to address receipt of initial ground-fault established for working on ungrounded delta alarms at RHIC. electrical systems that could have a ground-fault condition. BNL needs to establish the precautionary actions for safe work on ungrounded delta electrical systems that have a ground fault. JON 9 JON 10 JON 11 BNL needs to inspect all GE Spectra Series switches BNL failed to e
Type B Accident Investigation of the Arc Flash at Brookhaven National Laboratory, April 14, 2006 xi Executive Summary The Accident At 10:20 a.m., on April 14, 2006, a BNL Collider-Accelerator Department (C-AD) electrical engineer was injured by an arc flash at the Brookhaven National Laboratory (BNL) Relativistic Heavy Ion
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130.5 Arc Flash Risk Assessment. An arc flash risk assessment shall be performed and shall: (1) Determine if an arc flash hazard exists. If an arc flash hazard exists, the risk assessment shall determine: a) Appropriate safety-related work practices b) The arc flash boundary c) The PPE to be used within the arc flash boundary
About Brookhaven National Laboratory Established in 1947 on Long Island, Upton, New York, Brookhaven is a multi-program national laboratory operated by Brookhaven Science Associates for the U.S. Department of Energy (DOE). Six Nobel Prizes have been awarded for discoveries made at the Lab. Brookhaven has a staff of approximately 3,000 scientists,
Arc-flash analysis has been performed for this site (calculations, labeling and Arc-flash hazard analysis. arc-flash boundaries). Electrical safety training for operators and maintenance personnel. Arc-flash hazard training for operators and maintenance personnel. Arc-flash hazard training focusing on selecting and using the proper PPE.
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130.7(C)(15)(b) specify arc flash PPE category 1 or 2b Arc Flash Suit A total clothing system consisting of arc-rated shirt and pants and/or arc-rated coveralls and/or arc flash coat and pants (clothing system minimum arc rating of 40) Situations where a risk assessment indicates that PPE is required and where Table 130.7(C)(15)(a) and table .
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Quand un additif alimentaire est autorisé au niveau européen, celui-ci bénéficie d'un code du type Exxx. Les additifs sont classés selon leur catégories. Cependant, étant donné le développement de la liste et son caractère ouvert, la place occupée par un additif alimentaire dans la liste n'est plus nécessairement indicative de sa fonction. Sommaire 1 Tableau des colorants .
